TOKYO/LONDON (REUTERS)

The dollar softened on Friday as signs emerged of possible peace talks between the US and Iran, but headed for its first weekly gain in close to a month ​as investors remained nervous.

The dollar had been trading around flat in early trading, but later in the European session it softened more and was last down 0.23% at $98.595.

Brent crude futures turned negative in early afternoon trade in Europe.

The euro was 0.3% higher at $1.1172 and Sterling edged 0.2% higher, with stronger-than-expected UK retail sales for March barely moving the needle.

The dollar has drawn safe-haven demand and gained ground in March, ‌but gave back some of those gains this month as optimism over a potential resolution grew.

Meanwhile, the yen gained after four days of losses, rising 0.2% to 159.4 per dollar.

The Australian dollar rose 0.2% versus the greenback to $0.7143. New Zealand's kiwi rose 0.3% to $0.5871.

In cryptocurrencies, Bitcoin ​was little changed at $78,260.44